1. Field of the Invention
This invention relates to an apparatus for gapping a slide fastener chain at predetermined intervals along its length substantially simultaneously as applying a bottom end stop to the chain adjacent to the gapped section thereof.
2. Prior Art
Gapping apparatus known in the art comprise a cutting punch and a die cooperating in removing a group of fastener coupling elements from selected portions of a continuous slide fastener chain. The apparatus further comprise means for positioning and holding the coupling elements from opposite sides thereof during the gapping operation to prevent twisting or misalignment of the element which would otherwise occur under the influence of pressure applied by the punch. However, in the case where applying of bottom end stops simultaneously with gapping is desired as often done in the conventional practice, it was further necessary to provide means for retracting or otherwise moving the holding means out of the path of the bottom stop when advancing the fastener chain, because the bottom stop to be attached to the stringer tapes astride coupled pairs of fastener elements is sized larger than the coupled pair of fastener elements and would therefore impinge upon the holding means, blocking the feeding of the fastener chain.
There is disclosed in U. K. Patent Application No. GB 2021681.A a bottom stop applying and gapping mechanism which comprises a pair of slidable plates for positioning and holding the fastener elements, the plates being movable toward and away from each other and connected to a camming rod which operates in response to the lowering and raising of the punch to move the plates in the transverse direction of a slide fastener chain. This mechanism is not only complicated but also requires the plates to be retracted away from the element once a cycle of gapping operation is completed so as to permit advancing of the fastener chain.
Retraction of the plates creates a time lag between completion and initiation of a gapping and bottom stop applying operation. This time lag may be only appreciable when measured per cycle of operation but would aggregate considerably when measured over so many cycles required to finish the whole continuous length of a slide fastener chain.